title: Threshold-controlled ubiquitination of the EGFR directs receptor fate.
abstract: How the cell converts graded signals into threshold-activated responses is a question of great biological relevance. Here, we uncover a nonlinear modality of epidermal growth factor receptor (EGFR)-activated signal transduction, by demonstrating that the ubiquitination of the EGFR at the PM is threshold controlled. The ubiquitination threshold is mechanistically determined by the cooperative recruitment of the E3 ligase Cbl, in complex with Grb2, to the EGFR. This, in turn, is dependent on the simultaneous presence of two phosphotyrosines, pY1045 and either one of pY1068 or pY1086, on the same EGFR moiety. The dose-response curve of EGFR ubiquitination correlate precisely with the non-clathrin endocytosis (NCE) mode of EGFR internalization. Finally, EGFR-NCE mechanistically depends on EGFR ubiquitination, as the two events can be simultaneously re-engineered on a phosphorylation/ubiquitination-incompetent EGFR backbone. Since NCE controls the degradation of the EGFR, our findings have implications for how the cell responds to increasing levels of EGFR signalling, by varying the balance of receptor signalling and degradation/attenuation.
authors.affiliation: IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Sigismund
authors.forename: Veronica
authors.initials: V
authors.lastname: Algisi
authors.forename: Gilda
authors.initials: G
authors.lastname: Nappo
authors.forename: Alexia
authors.initials: A
authors.lastname: Conte
authors.forename: Roberta
authors.initials: R
authors.lastname: Pascolutti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cuomo
authors.forename: Tiziana
authors.initials: T
authors.lastname: Bonaldi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Argenzio
authors.forename: Lisette G G C
authors.initials: LG
authors.lastname: Verhoef
authors.forename: Elena
authors.initials: E
authors.lastname: Maspero
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Bianchi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Capuani
authors.forename: Andrea
authors.initials: A
authors.lastname: Ciliberto
authors.forename: Simona
authors.initials: S
authors.lastname: Polo
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Di Fiore
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004705:Endocytosis / Q000502:physiology*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D051380:GRB2 Adaptor Protein / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D059748:Proteolysis; D050721:Proto-Oncogene Proteins c-cbl / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination / Q000502:physiology*
chemical_list: D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D050721:Proto-Oncogene Proteins c-cbl; C512478:EGFR protein, human; D066246:ErbB Receptors; C067419:CBL protein, human